Destruction of the Inertial Recirculation by the Annual Wind Migration

Abstract

The effect of annual wind migration on the inertial recirculation is investigated using quasigeostrophic models. It is found that recirculation cells can he suppressed significantly by the wind migration. The two key dynamic conditions for the suppression are 1) the mismatch of formation timescales between the western boundary current and recirculation, and 2) the interaction between the two neighboring recirculation cells, which is related to chaotic intercell transport. The first condition tends to disconnect the potential vorticity anomaly source on the western boundary from the recirculation cell, while the second condition can generate strong eddy enstrophy flux and therefore the mixing of potential vorticity anomalies. Both conditions tend to destroy the potential vorticity anomaly, and in turn the recirculation.